She said: “We know that we are targets and have security advice every two or three months but that’s very different to actually experiencing it and then seeing the impact on other people, on constituents, on the police, on the tourists and everyone around - it’s different when it actually happens to knowing it’s possible.

“We don’t want parliament to change - part of democracy means there has to be access to parliament and MPs.

“What the implications are of this is something we’re going to have to work through.”